The present invention relates to an abrasive wheel to grind or cut a variety of materials such as granite, brick, concrete block or the like by using abrasive means, and more particularly, to an abrasive wheel which permits the reduction in friction heat generated during the abrasive operation through an increased cooling action and at the same time permits effective discharge of cut sludge by causing an increased difference in the velocity of sludge flow at radially remote and close positions within an abrasive segment.
A conventional abrasive wheel 100, as shown in FIG. 1, comprises a cup type core part 120 with an opening H for mounting a tool transmitting motive power (not shown) at the center, sucking holes 120H distributed around the opening H and a shank 110 around the core part 120. The shank 110 includes ordinary tips 200 circumferentially on its base. The ordinary tips 200 act as cutting blades by means of welding, soldering or adhesion. The tips consist of a calcined product including diamond, CBN or other abrasives (hereinafter referred to as xe2x80x9cabrasivesxe2x80x9d) and powder of the material comprising metals, resins, ceramics or the like for holding or binding together the abrasives and allowing continuous regenerating action.
In that case, the core part 120 is a cup with a relatively large diameter and the suction holes 120H formed on the core part represent mere holes for flow under the sucking force of a dust collector (not shown).
The abrasive work using such a conventional abrasive wheel 100 is conducted in dry process, and even with a dust collector operating, a considerable amount of dust from the body under abrasion tends to be discharged to the outside due to the centrifugal force of the abrasive wheel. The dust collecting efficiency is decreased as some dust inevitably spills outside the safety cover wherein the hood for the dust collector is provided and the working environment is polluted with the dust, causing a problem. Accordingly, the conventional abrasive wheel, which depends on the cooling method or heat dissipating method with a low efficiency based on the mere rapid chip extracting function of a dust collector, suffers from carbonization or oxidization of the abrasives over a long period of continuous operation due to the increase in the thermal shock exerted on the abrasives including diamond. The shock originates from the friction heat between the body under abrasion and the abrasive wheel, whereby a premature falling-off of the tip 200 takes place.
In addition, the difference between the rotation speed of the abrasive segments 130 at their radially inner positions and their outer positions of the shank 110 is very meager. The sucking force by the dust collector is not oriented in line with the discharging direction of the slurry flow. Thus, the discharge of slurry is not smoothly conducted and the abrasion performance is reduced.
FIG. 2 illustrates an abrasive segment that failed to result in a uniform wear because there was no difference in the shape of the radially inner and outer part of the abrasive segment. As a result, the outer part of the abrasive segment is worn out ahead of time.
Accordingly, the object of the present invention which is devised to resolve the above-described disadvantage is to provide an abrasive wheel, wherein air sucking holes are located at positions relatively far from the center of the abrasive wheel and proximate to the abrasive segments for the ultimate purpose of promoted cooling. The difference between the somewhat radially inward velocity of the flow, including cut sludge at radially distal positions and proximal positions within the abrasive segments, is large enough to facilitate the discharge of the sludge to help improve the cutting performance. Furthermore, the combined segments, each comprising a long tip and a short tip, are attached to the circular shank at regular intervals to induce uniform wear of the abrasive segments.
To accomplish the above objects, an abrasive wheel to grind or cut a variety of materials in accordance with the present invention comprises a core part fixed to a tool transmitting motive power and long tips and short tips alternately attached on the base surface of a shank around the core part. The tips are arranged to cover the base surface with space therebetween at predetermined intervals along the circumference of the shank.
The long and short tips are preferably shaped so that the tips circumferential area increases with the increasing distance from the central part.
The long and short tips may be shaped so that they have a certain curved portion in the direction of rotation.
A suction hole may be located between the long tips and inside of the short tip. The suction hole may be surrounded by an inclined wall surface to guide cut chips according to the rotation direction of an abrasive wheel.